Conventionally, among light source devices used for illumination in an image scanning device, there exist configurations in which a light source such as LEDs are placed at the ends of a transparent light guide extending in the main scanning direction of the image scanning device, cause light to be input, and cause light to be output from a side face of the light guide into which the light is input (for example, see Patent Literature 1 to 4). These are referred to as sidelight-type light source devices.
In the scanning device of Patent Literature 1, the light guide includes a columnar part into which light from a light-emitting element is input from the ends, and includes a convex part that projects out approximately perpendicular to the lengthwise direction of the columnar part near the ends of the columnar part. A holder includes an engaging part that engages with the convex part. The engaging part engages with the convex part therebetween in the lengthwise direction of the light guide, such that the convex part is movable with respect to engaging part in the case in which the relative positions of the light guide and a frame change due to temperature changes.
In a light source device as described in Patent Literature 2, optical filters are placed opposite the end faces of the light guide. Also, in the light source device as described in Patent Literature 3 and 4, countermeasures are provided against expansion and contraction due to temperature changes near the light guide. Note that there are configurations that place light sources at both end faces of the light guide, as described in Patent Literature 2 and 3, and configurations that place a light guide at one end face of the light guide, as described in Patent Literature 4.
The light source devices described in Patent Literature 5 to 9 are other examples of a light source device that places a light source at one end face of a light guide. With respect to a light guide as described in Patent Literature 5, there are also light guides whose ends are curved, as described in Patent Literature 6 to 9. Additionally, as described in FIG. 10 of Patent Literature 9, there is also a configuration in which both ends of the light guide are curved, and light sources are placed at both end faces of the curved light guide.
As another light source device used for illumination in an image scanning device, there is a configuration in which light sources such as a plurality of light-emitting diodes (LEDs) are arranged in the main scanning direction of the image scanning device (for example, see Patent Literature 10, 11, and 12). Patent Literature 10 and 11 describe configurations in which light emitted from the LEDs is guided by a light guide member, and radiated onto a reflector. Also, Patent Literature 12 describes a configuration in which light output from the LEDs is radiated onto a reflector. These are referred to as LED array-type light source devices.
Patent Literature 10, 11, and 12 also describe a reflector (a first mirror) constituting an image-forming optical system of an image scanning device. Particularly, FIG. 5 of Patent Literature 11 discloses a reflector (first mirror) supported by a carriage of an image scanning device.
Patent Literature 13 and 14 describe a reflector (first mirror) supported by a carriage of an image scanning device. In Patent Literature 13 and 14, both ends of the reflector (first mirror) are supported.